As many as one in ten adults in the UK have some form of liver disease (British Liver Trust. Alcohol and liver disease. Ringwood: British Liver Trust, 2006). Liver disease is currently the fifth most common cause of mortality for both men and women (Department of Health. Quality Strategy Team Report on Liver Disease: A seeping study into the nature and burden of the disease, 2006). However, whilst the mortality rates for the other four major causes of death are falling, the trend for liver disease is rising in both sexes at an alarming rate and there has been a five-fold increase in the prevalence of liver cirrhosis in the last 30 years. The current childhood obesity epidemic, increasing alcohol misuse and viral hepatitis are all contributing to this. The problem with liver disease is that often symptoms of the disease are not apparent until the disease reaches an advanced stage. Thus, there is a pressing need for a reliable diagnostic tool for liver disease to identify early disease and to target therapies to those patients that may benefit (e.g., antiviral therapy in progressive hepatitis C, weight reduction surgery in fatty liver disease).
The current accepted practice, or “gold standard”, for diagnosing liver disease is an ultrasound-guided liver biopsy. This is less than ideal as there is a small but significant complication risk (1:1000 of severe bleeding, especially in coagulopathic patients). Furthermore, only 0.002% of the liver is examined, and there is great intraand inter-observer variability in histological interpretation (see, e.g., Sampling error and intra-observer variation in liver biopsy in patients with chronic HCV infection. Regev A et al, Am J Gastroenterol. 2002 October; 97(10):2614-8. Histologic variation of grade and stage of non-alcoholic fatty liver disease in liver biopsies. Janiec O J et al, Obes Surg. 2005 April; 15(4):497-501. Assessment of Hepatic Steatosis by Expert Pathologists: The End of a Gold Standard. El Badry A M et al, Annals of Surgery 250(5), November 2009, 691-697).
A relatively high proportion of patients referred for liver biopsy have high liver iron. As an example, approximately one-third of the patients recruited to our study below had high liver iron. Fibrosis cannot be assessed accurately in this population using a non-invasive imaging procedure such as T1 mapping without some kind of correction.
Accordingly, there is a need to address the aforementioned deficiencies and inadequacies.